Methods of forming patterns using photoresist polymers and methods of manufacturing semiconductor devices

ABSTRACT

A photoresist polymer includes a first repeating unit and a second repeating unit. The first repeating unit includes a fluorine leaving group that is configured to be removed by a photo-chemical reaction. The second repeating unit includes a silicon-containing leaving group that is configured to be removed by the fluorine leaving group when the fluorine leaving group is removed from the first repeating unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC §119 to Korean PatentApplication No. 10-2014-0178949, filed on Dec. 12, 2014 in the KoreanIntellectual Property Office (KIPO), the contents of which areincorporated by reference herein in their entirety.

BACKGROUND 1. Field

Example embodiments relate to photoresist polymers, photoresistcompositions, methods of forming patterns and/or methods ofmanufacturing semiconductor devices. More particularly, exampleembodiments relate to photoresist polymers including leaving groups,photoresist compositions including the photoresist polymers, methods offorming patterns and/or methods of manufacturing semiconductor devicesusing the photoresist polymers.

2. Description of Related Art

A photolithography process may be utilized for a formation of variouspatterns included in a semiconductor device. For example, a photoresistlayer may be divided into an exposed portion and a non-exposed portionby, e.g., an exposure process, and the exposed portion may be removed bya developing process to form a photoresist pattern. The object layer maybe patterned using the photoresist pattern as an etching mask to form adesired pattern.

However, an intermediate component such as an acid may be generated fromthe exposure process, and a resolution of the photolithography processmay be deteriorated by the intermediate component.

SUMMARY

Example embodiments provide a photoresist polymer having an improvedresolution.

Example embodiments provide a photoresist composition including thephotoresist polymer.

Example embodiments provide a method of forming a pattern using thephotoresist polymer.

Example embodiments provide a method of manufacturing a semiconductordevice using the photoresist polymer.

According to example embodiments, a photoresist polymer includes a firstrepeating unit and a second repeating unit. The first repeating unitincludes a fluorine leaving group configured to be removed by aphoto-chemical reaction. The second repeating unit includes asilicon-containing leaving group configured to be removed by thefluorine leaving group when the fluorine leaving group is removed fromthe first repeating unit.

In example embodiments, the silicon-containing leaving group may includesilyl ether.

In example embodiments, the silicon-containing leaving group may includetrimethylsilyl (TMS), tert-butyldimethylsilyl (TBDMS), triisopropylsilyl(TIPS) and/or tert-butyldiphenylsilyl (TBDPS).

In example embodiments, the second repeating unit may be represented byChemical Formula 1.

In Chemical Formula 1, R₁ may be a divalent group selected from styrene,hydroxystyrene, acrylate, C₁-C₆ alkylene, arylene, carbonyl, oxy, aC₂-C₃₀ unsaturated aliphatic group, and a combination thereof. R₂, R₃and R₄ may be independently hydrogen, a C₁-C₂₀ alkyl group, a C₃-C₂₀cycloalkyl group or a C₆-C₃₀ aromatic group, and R₂, R₃ and R₄ may bethe same as or different from each other.

In example embodiments, the photoresist polymer may be represented byChemical Formula 2.

In Chemical Formula 2, R₁ and R₅ may be each independently a divalentgroup selected from styrene, hydroxystyrene, acrylate, C₁-C₆ alkylene,arylene, carbonyl, oxy, a C₂-C₃₀ unsaturated aliphatic group, and acombination thereof. R₂, R₃ and R₄ may be independently hydrogen, aC₁-C₂₀ alkyl group, a C₃-C₂₀ cycloalkyl group or a C₆-C₃₀ aromaticgroup, and R₂, R₃ and R₄ may be the same as or different from eachother. R₆ may be a C₁-C₂₀ alkyl group, a C₁-C₂₀ allyl group, a C₃-C₂₀cycloalkyl group, a C₆-C₃₀ aromatic group, a hydroxyl group, ahydroxyalkyl group, or a C₁-C₂₀ alkoxy group. Each a and b may representa mole ratio ranging from about 0.4 to about 0.6, and a sum of a and bmay be 1.

In example embodiments, in Chemical Formula 2, fluorine (F) and hydrogen(H) may be positioned in a staggered conformation or an anti-periplanarconfiguration.

According to example embodiments, a photoresist composition includes aphotoresist polymer including a repeating unit combined with asilicon-containing leaving group, a fluorine-containing sourceconfigured to provide an active fluorine, and a solvent.

In example embodiments, wherein the repeating unit may be represented bythe above Chemical Formula 1.

In example embodiments, the fluorine-containing source may include asalt solution of a fluorine ion. The salt solution may be an organicsalt solution or an inorganic salt solution.

In example embodiments, the fluorine-containing source may include anammonium fluoride solution or an alkali metal fluoride solution.

In example embodiments, the fluorine-containing source may beincorporated in the photoresist polymer as a repeating unit thereof.

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2.

In example embodiments, the photoresist composition may further includea photoacid generator and/or a sensitizer.

According to example embodiments, a method of forming a pattern includesforming a photoresist layer on an object layer, performing an exposureprocess on the photoresist layer, and forming a photoresist pattern. Thephotoresist layer includes photoresist polymer that includes a firstrepeating unit and a second repeating unit. The first repeating unitincludes a fluorine leaving group and the second repeating unit includesa silicon-containing leaving group. The exposure process induces areaction between the fluorine leaving group and the silicon-containingleaving group. The forming a photoresist pattern includes removing anexposed portion of the photoresist layer.

In example embodiments, the performing the exposure process may includeinducing an elimination reaction may in the first repeating unit so thatthe fluorine leaving group may be separated from the first repeatingunit.

In example embodiments, the performing the exposure process may includeincreasing a degree of unsaturation at the exposed portion by theexposure process.

In example embodiments, the reaction induced by the performing theexposure process may include separating the fluorine leaving group fromthe first repeating unit and transferring the separated fluorine leavinggroup to the second repeating unit to attack the silicon-containingleaving group.

In example embodiments, the exposed portion may be more hydrophilic andpolar than a non-exposed portion of the photoresist layer after theperforming the exposure process.

In example embodiments, the reaction induced by the performing theexposure process may include removing the silicon-containing leavinggroup from the exposed portion so that a hydroxyl group or a carboxylicgroup may be created in the exposed portion.

In example embodiments, the removing the exposed portion of thephotoresist layer may include performing a developing process or a dryetching process.

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2.

In example embodiments, the object layer may be patterned using thephotoresist pattern as an etching mask.

According to example embodiments, a method of forming a pattern includesforming a photoresist layer on an object layer by coating a photoresistcomposition on the object layer, performing an exposure process on thephotoresist layer, and removing an exposed portion of the photoresistlayer to form a photoresist pattern. The photoresist compositionincludes a photoresist polymer, a fluorine-containing source configuredto provide an active fluorine and a solvent. The photoresist polymerincludes a repeating unit combined with a silicon-containing leavinggroup. The exposure process performed on the photoresist layer transfersthe active fluorine from the fluorine-containing source to thesilicon-containing leaving group.

In example embodiments, the active fluorine may include one of afluorine ion and a fluorine radical.

In example embodiments, the photoresist composition may further includea photoacid generator and/or a sensitizer.

In example embodiments, the fluorine-containing source may be providedas a fluorine ion salt, or incorporated in the photoresist polymer as arepeating unit thereof.

In example embodiments, the performing the exposure process may includeinducing a reaction that combines the active fluorine may with thesilicon-containing leaving group, and removing the active fluorinecombined with the silicon-containing leaving group from the photoresistpolymer.

According to example embodiments, a method of manufacturing asemiconductor device includes forming a mold structure by alternatelyand repeatedly stacking insulating interlayers and sacrificial layers ona substrate, forming a photoresist layer on the mold structure bycoating a photoresist composition that includes a photoresist polymer onthe mold structure, performing an exposure process on a lateral portionof the photoresist layer to form an exposed portion in the photoresistlayer, removing the exposed portion to form a photoresist pattern,partially removing a lateral portion of the mold structure using thephotoresist pattern as an etching mask, forming a plurality of verticalchannels through a central portion of the mold structure, and replacingthe sacrificial layers with gate lines. The photoresist compositionincludes a fluorine-containing source configured to provide an activefluorine and solvent. The photoresist polymer includes a repeating unitcombined with a silicon-containing leaving group.

In example embodiments, the method may further include converting themold structure into a stepped mold structure by repeatedly performingthe performing the exposure process on the lateral portion of thephotoresist layer, the removing the exposed portion to form thephotoresist pattern, and the partially removing the lateral portion ofthe mold structure.

In example embodiments, the performing the exposure process may includea chemical reaction that removes the silicon-containing leaving groupfrom the exposed portion, and the exposed portion may be at least one ofmore hydrophilic and more polar than a non-exposed portion of thephotoresist layer after the silicon-containing leaving group is removedfrom the exposed portion.

According to example embodiments, a method of forming a patternincludes: forming a photoresist layer on an object layer, thephotoresist layer including a photoresist polymer includes a repeatingunit that includes a silicon-containing leaving group, the photoresistlayer including a fluorine source configured to provide active fluorinein response to exposure from light; performing an exposure process onthe photoresist layer to separate the active fluorine from the fluorinesource, the performing the exposure process including inducing areaction between the active fluorine and the silicon-containing leavinggroup that removes the silicon-containing leaving group from thephotoresist polymer; and forming a photoresist pattern by removing anexposed portion of the photoresist layer.

In example embodiments, the photoresist polymer may include a firstrepeating unit that includes a fluorine leaving group configured to beremoved by the exposure process. The fluorine leaving group may be thefluorine source. The repeating unit that includes the silicon-containingleaving group may be a second repeating unit.

In example embodiments, the fluorine source may include a salt solutionof a fluorine ion.

In example embodiments, the repeating unit may include one of silylether and a functional group represented by the above Chemical Formula1.

In example embodiments, a semiconductor device may be manufactured byforming a mold structure by alternately and repeatedly stackinginsulating interlayers and sacrificial layers on a substrate, performingthe above method of forming a pattern to form a photoresist pattern onthe mold structure, removing the portion of the mold structure using thephotoresist pattern as an etching mask, forming a plurality of verticalchannels through a central portion of the mold structure, replacing thesacrificial layers with gate lines.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1 to 33 represent non-limiting, example embodiments asdescribed herein.

FIGS. 1 to 6 are cross-sectional views illustrating a method of forminga pattern in accordance with example embodiments;

FIGS. 7 to 14 are cross-sectional views illustrating a method of forminga pattern in accordance with example embodiments; and

FIGS. 15 to 33 are top plan views and cross-sectional views illustratinga method of manufacturing a semiconductor device in accordance withexample embodiments.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Various example embodiments will be described more fully hereinafterwith reference to the accompanying drawings, in which some exampleembodiments are shown. Inventive concepts may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these example embodiments areprovided so that this description will be thorough and complete, andwill fully convey the scope of the inventive concepts to those skilledin the art. In the drawings, the sizes and relative sizes of layers andregions may be exaggerated for clarity. Like reference characters and/ornumerals in the drawings denote like elements, and thus theirdescription may not be repeated.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Other words used to describe therelationship between elements or layers should be interpreted in a likefashion (e.g., “between” versus “directly between,” “adjacent” versus“directly adjacent,” “on” versus “directly on”). As used herein, theterm “and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, third,fourth etc. may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of inventive concepts.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of inventiveconcepts. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Example embodiments are described herein with reference tocross-sectional illustrations that are schematic illustrations ofidealized example embodiments (and intermediate structures). As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, example embodiments should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, an implanted region illustrated as arectangle will, typically, have rounded or curved features and/or agradient of implant concentration at its edges rather than a binarychange from implanted to non-implanted region. Likewise, a buried regionformed by implantation may result in some implantation in the regionbetween the buried region and the surface through which the implantationtakes place. Thus, the regions illustrated in the figures are schematicin nature and their shapes are not intended to illustrate the actualshape of a region of a device and are not intended to limit the scope ofinventive concepts.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Although corresponding plan views and/or perspective views of somecross-sectional view(s) may not be shown, the cross-sectional view(s) ofdevice structures illustrated herein provide support for a plurality ofdevice structures that extend along two different directions as would beillustrated in a plan view, and/or in three different directions aswould be illustrated in a perspective view. The two different directionsmay or may not be orthogonal to each other. The three differentdirections may include a third direction that may be orthogonal to thetwo different directions. The plurality of device structures may beintegrated in a same electronic device. For example, when a devicestructure (e.g., a memory cell structure or a transistor structure) isillustrated in a cross-sectional view, an electronic device may includea plurality of the device structures (e.g., memory cell structures ortransistor structures), as would be illustrated by a plan view of theelectronic device. The plurality of device structures may be arranged inan array and/or in a two-dimensional pattern.

Photoresist Polymers

A photoresist polymer in accordance with example embodiments may includea first repeating unit and a second repeating unit that may bealternately and repeatedly propagated in a backbone chain.

The backbone chain may include a carbon chain included in a photoresistmaterial. For example, the backbone chain may include a polymer chainsuch as novolak, polystyrene, polyhydroxystyrene (PHS), polyacrylate,polymethacrylate, polyvinyl ester, polyvinyl ether, polyolefin,polynorbornene, polyester, polyamide, polycarbonate or the like. Inexample embodiments, novolak, polystyrene, PHS or polyacrylate may beused as the backbone chain.

The first repeating unit may include a halogen leaving group. Forexample, the first repeating unit may include a fluorine leaving group.In example embodiments, the fluorine leaving group may be configured tobe removed or separated from the first repeating unit by aphoto-chemical reaction induced by, e.g., an ultraviolet (UV) exposureprocess. In example embodiments, the fluorine leaving group may beremoved in a form of hydrogen fluoride (HF) from the first repeatingunit.

The second repeating unit may include a leaving group that is configuredto (and/or capable of) being reacted with the fluorine leaving groupseparated from the first repeating unit and configured to (and/orcapable of) being removed from the second repeating unit. In exampleembodiments, the second repeating unit may include a silicon-containingleaving group.

In example embodiments, the silicon-containing leaving group may includesilyl ether. For example, the silicon-containing leaving group mayinclude trimethylsilyl (TMS), tert-butyldimethylsilyl (TBDMS),triisopropylsilyl (TIPS), tert-butyldiphenylsilyl (TBDPS) or acombination thereof.

For example, the second repeating unit including the silicon-containingleaving group may be represented by the following Chemical Formula 1.

In Chemical Formula 1, R₁ may be a divalent group selected styrene,hydroxystyrene, acrylate, C₁-C₆ alkylene, arylene, carbonyl, oxy, aC2-C30 unsaturated aliphatic group or a combination thereof. R2, R3 andR4 may be independently hydrogen, a C1-C20 alkyl group, a C3-C20cycloalkyl group or a C6-C30 aromatic group. R2, R3 and R4 may be thesame as or different from each other.

In example embodiments, the photoresist polymer may be represented bythe following Chemical Formula 2.

In Chemical Formula 2, a right repeating unit denoted as “b” maycorrespond to the first repeating unit, and a left repeating unitdenoted as “a” may correspond to the second repeating unit.

R1 to R4 may be substantially the same as those defined in the aboveChemical Formula 1. R5 may be a divalent group selected styrene,hydroxystyrene, acrylate, C1-C6 alkylene, arylene, carbonyl, oxy, aC2-C30 unsaturated aliphatic group or a combination thereof, similarlyto R1. R6 may be a C1-C20 alkyl group, a C1-C20 allyl group, a C3-C20cycloalkyl group, a C6-C30 aromatic group, a hydroxyl group, ahydroxyalkyl group, or a C1-C20 alkoxy group. Each a and b may representa mole ratio. In example embodiments, each a and b may range from about0.4 to about 0.6, and a sum of a and b may be 1.

In example embodiments, the first and second repeating units may bealternately repeated in the backbone chain. In this case, the first andsecond repeating units may be combined by a ratio of 1:1 to form onepolymerized repeating unit, and the polymerized repeating units may berepeated in the backbone chain.

In this case, the photoresist polymer may be represented by thefollowing Chemical Formula 3.

For example, in Chemical Formulas, n may be an integer ranging fromabout 10 to about 10,000.

In the above Chemical Formula 3, a hydrogen atom and a fluorine atomincluded in the first repeating unit may be positioned in aconfiguration for facilitating an elimination reaction photo-chemicallyinduced. For example, the hydrogen atom and the fluorine atom may bepositioned in a staggered conformation or a trans configuration. Inexample embodiments, the hydrogen atom and the fluorine atom may bepositioned in an anti-periplanar configuration.

Accordingly, the elimination reaction may occur through the exposureprocess using, e.g., an extreme ultraviolet (EUV) light source so thatHF may be removed. As a result, a double bond may be created in thefirst repeating unit so that a degree of unsaturation therein may beincreased.

The fluorine atom removed from the first repeating unit may be convertedto an active fluorine such as a fluorine ion (F−) or a fluorine radical(F−) to attack a silicon atom of the second repeating unit. Thus, thesilicon-containing leaving group may be removed from the secondrepeating unit, and a hydroxyl group or carboxylic acid may be combinedat a position from which the silicon-containing leaving group isdeparted. Therefore, a portion of the photoresist polymer from which theleaving groups are separated may have improved hydrophilicity andetching rate.

In example embodiments, the photoresist polymer may serve as apositive-type photoresist material. In this case, a portion of thephotoresist polymer exposed to light (e.g., exposed portion) may beremoved by an etching process or a developing process. The portion ofthe photoresist polymer that is not exposed to light (e.g., non-exposedportion) may remain after the exposed portion is removed by the etchingprocess or the developing process.

Photoresist Compositions

A photoresist composition according to example embodiments may include aphotoresist polymer that may include a repeating unit to which asilicon-containing leaving group may be combined, a fluorine-containingsource providing an active fluorine and a solvent.

The silicon-containing leaving group may include silyl ether such asTMS, TBDMS, TIPS or TBDPS. In this case, the repeating unit includingthe silicon-containing leaving group may be represented by the aboveChemical Formula 1.

-   In example embodiments, the fluorine-containing source may be    incorporated in the photoresist polymer as a repeating unit thereof.    In this case, the photoresist polymer may be polymer of a first    repeating unit including a fluorine leaving group and a second    repeating unit including the silicon-containing leaving group as    described above.

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2. In example embodiments, the photoresistpolymer may be represented by the above Chemical Formula 3.

In example embodiments, the fluorine-containing source may include anorganic salt solution or an inorganic salt solution of a fluorine ion.For example, the organic salt solution of the fluorine ion may includean organic fluoride ammonium salt such as tetrabutylammonium fluoride(TBAF). The inorganic salt solution of the fluorine ion may includefluoride ammonium (NH4F), or an alkali metal fluoride such as KF, NaF,CsF, etc.

The organic salt or the inorganic salt of the fluorine ion may beco-present with the photoresist polymer so that the fluorine ion may becreated from the fluorine-containing source during an exposure processto attack a silicon atom of the silicon-containing leaving group. Thus,the silicon-containing leaving group may be removed from the repeatingunit of the photoresist polymer.

The solvent may include an organic solvent having a good solubility fora polymer material, and a good coatability (e.g., good coatingcharacteristics) for a formation of a uniform photoresist layer.Examples of the solvent may include cyclohexanone, cyclopentanone,tetrahydrofuran (THF), dimethylformamide, propylene glycol monomethylether acetate (PGMEA), ethyl lactate, methyl ethyl ketone, benzene ortoluene. These may be used alone or in a combination thereof.

In example embodiments, if the fluorine-containing source is provided asthe organic salt solution or the inorganic salt solution, a phaseseparation between the solution and the solvent may occur. Thus, asurfactant may be added in the composition so that a contact and/or areaction between the fluorine-containing source and the photoresistpolymer may be facilitated. The surfactant may include, e.g., asorbitol-based agent or an alcohol having a relatively long carbonchain.

In example embodiments, the photoresist composition may further includea photoacid generator (PAG). The PAG may include any compounds capableof generating an acid by an exposure process. For example, the PAG mayinclude an onium salt, an aromatic diazonium salt, a sulfonium salt, atriarylsulfonium salt, a diarylsulfonium salt, a monoarylsulfonium salt,an iodonium salt, a diaryliodonium salt, nitrobenzyl ester, disulfone,diazo-disulfone, sulfonate, trichloromethyl triazine,N-hydroxysuccinimide triflate, or the like. These may be used alone orin a combination thereof.

The acid (e.g., proton (H+)) generated from the PAG may serve as acatalyst facilitating a fluorine removal from the polymer represented bythe above Chemical Formula 2 or Chemical Formula 3. For example, whileperforming a photo-chemical reaction by the exposure process, some ofthe first repeating units in an exposed portion may remain in a statethat the fluorine leaving group may not be removed. The fluorine leavinggroups included in the some of the first repeating units may be removedby the acid from the PAG.

If the PAG is excessively included in the photoresist composition,defects of a photoresist pattern may be caused by an acid diffusion.Thus, the PAG may be added in the photoresist composition only by acatalytic amount.

In example embodiments, the photoresist composition may further includea sensitizer for facilitating the photo-chemical reaction. An amount ofphotons may be amplified by the sensitizer, and thus a sufficient amountof the active fluorine may be obtained.

The sensitizer may include, e.g., benzophenone, benzoyl, thiophene,naphthalene, anthracene, phenanthrene, pyrene, coumarin, thioxantone,acetophenone, naphtoquinone, anthraquinone, or the like. These may beused alone or in a combination thereof.

The photoresist composition may further include an additive forimproving chemical and physical properties of a photoresist layer formedfrom the composition. The additive may include, e.g., a leveling agent,a viscosity modifier, or the like.

The photoresist composition may be a positive-type. For example, whenthe exposure process may be performed on the photoresist layer formedfrom the composition, the active fluorine including a fluorine ion or afluorine radical may be generated from the fluorine-containing source atan exposed portion. The silicon-containing leaving group of thephotoresist polymer may be removed by the active fluorine. A hydroxylgroup or carboxylic acid may be created at a site from which thesilicon-containing leaving group is removed. Thus, the exposed portionmay have a hydrophilicity and/or a solubility greater than those of anon-exposed portion. Accordingly, the exposed portion may be selectivelyremoved by an etching process or a developing process to form aphotoresist pattern.

Method of Forming Patterns

FIGS. 1 to 6 are cross-sectional views illustrating a method of forminga pattern in accordance with example embodiments. For example, FIGS. 1to 6 illustrate the method of forming patterns utilizing theabove-mentioned photoresist polymer or photoresist composition.

Referring to FIG. 1, an object layer 110 may be formed on a substrate100. The substrate 100 may include a semiconductor substrate or asemiconductor-on-insulator substrate. For example, the substrate 100 mayinclude silicon substrate, a germanium substrate, a silicon-germaniumsubstrate, a silicon-on-insulator (SOI) substrate or agermanium-on-insulator (GOI) substrate. In example embodiments, thesubstrate 100 may include a group III-V compound such as GaP, GaAs orGaSb.

An image may be transferred from a photoresist pattern to the objectlayer 110 so that the object layer 110 may be converted to a desired(and/or alternatively predetermined) pattern. In example embodiments,the object layer 110 may be formed of an insulative material such assilicon oxide, silicon nitride or silicon oxynitride. In exampleembodiments, the object layer 110 may be formed of a conductive materialsuch as a metal, a metal nitride, a metal silicide or a metal silicidenitride. In example embodiments, the object layer 110 may be formed of asemiconductor material such as polysilicon.

The object layer 110 may be formed by at least one deposition process.For example, the objection layer 100 may be formed using at least one ofa chemical vapor deposition (CVD) process, a plasma enhanced chemicalvapor deposition (PECVD) process, a low pressure chemical vapordeposition (LPCVD) process, a high density plasma chemical vapordeposition (HDP-CVD) process, a spin coating process, a sputteringprocess, an atomic layer deposition (ALD) process, and a physical vapordeposition (PVD) process.

Referring to FIG. 2, an anti-reflective layer 120 and a photoresistlayer 130 may be sequentially formed on the object layer 110.

The anti-reflective layer 120 may be formed using an aromatic organiccomposition such as a phenol resin or a novolak resin, or an inorganicmaterial such as silicon oxynitride. The anti-reflective layer 120 maybe formed by a coating process(e.g., a spin coating process, a dipcoating process or a spray coating process). The anti-reflective layer120 may also serve as a planarization layer. In example embodiments, theformation of the anti-reflective layer 120 may be omitted.

The photoresist layer 130 may be formed using the photoresistcomposition according to example embodiments. As described above, thephotoresist composition may include a photoresist polymer that mayinclude a repeating unit to which a silicon-containing leaving group maybe combined, a fluorine-containing source providing an active fluorine,and a solvent. The photoresist composition may optionally include asurfactant, a PAG and/or a sensitizer.

In example embodiments, the fluorine-containing source may beincorporated in the photoresist polymer. In this case, the photoresistpolymer may be a polymer from a first repeating unit including afluorine leaving group, and a second repeating unit including thesilicon-containing leaving group

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2 or Chemical Formula 3.

In example embodiments, the fluorine-containing source may be providedas an organic salt solution or an inorganic salt solution of a fluorineion.

The photoresist layer 130 may be formed by, e.g., a spin coatingprocess, a dip coating process or a spray coating process. In exampleembodiments, the photoresist composition may be coated to form apreliminary photoresist layer, and the preliminary photoresist layer maybe cured by, e.g., a baking process to form the photoresist layer 130.

Referring to FIG. 3, an exposure process may be performed on thephotoresist layer 130.

In example embodiments, an exposure mask 140 may be placed on thephotoresist layer 130, and a light may be irradiated through an openingor a transmission portion included in the exposure mask 140.Non-limiting examples of a light source used in the exposure process mayinclude ArF, KrF, an electron beam, Mine or EUV.

The photoresist layer 130 may be divided into an exposed portion 133 anda non-exposed portion 135. In example embodiments, a chemical structurein the exposed portion 133 may be modified through a mechanism shown bythe following Reaction Scheme 1.

For example, according to Reaction Scheme 1, the fluorine-containingsource may be incorporated in the photoresist polymer as the firstrepeating unit, and the silicon-containing leaving group of the secondrepeating unit may include TBDPS.

Referring to Reaction Scheme 1, the photoresist layer 130 may besubstantially non-polar and/or hydrophobic before the exposure process.In an operation S10, as illustrated in FIG. 3, when the exposure processis initiated, photons may be generated so that fluorine may be separatedfrom the first repeating unit. In example embodiments, the photoresistcomposition may include the sensitizer. Accordingly, an amount or thenumber of the photons generated by the exposure process may beincreased.

Fluorine (F) and hydrogen (H) in the first repeating unit may bepositioned in a trans or anti-periplanar configuration. Thus, anelimination reaction of fluorine and hydrogen may be easily induced bythe photons. Accordingly, a double bond may be created in the firstrepeating unit of the exposed portion 133 so that a degree ofunsaturation may be increased, and a fluorine ion (F-) may be generatedas the active fluorine. In example embodiments, a fluorine radical maybe generated by the photons, and proton (H+) may be also generated bythe elimination reaction.

The fluorine ion generated in the operation S10 may be transferred tothe second repeating unit to attack a silicon atom of thesilicon-containing leaving group.

Accordingly, in an operation S12, the silicon-containing leaving groupmay be combined with the fluorine ion to be removed from the secondrepeating unit or the photoresist polymer. For example, a carboxylateion may be created in the second repeating unit from which thesilicon-containing group is departed.

In an operation S14, the carboxylate ion created in the second repeatingunit, and the proton created in the operation S10 may be combined sothat. e.g., carboxylic acid may be created. Thus, the exposed portion133 may become more polar and/or hydrophilic than the non-exposedportion 135.

In example embodiments, e.g., if the photoresist polymer has a structureof the above Chemical Formula 3, the fluorine leaving group included inthe first repeating unit and the silicon-containing leaving groupincluded in the second repeating unit may be substantially reacted by aratio of 1:1. Thus, the exposed portion 133 and the non-exposed portion135 may be formed in a desired resolution by the exposure processwithout an assistance of the PAG.

In example embodiments, the photoresist composition may include acatalytic amount of the PAG. If the fluorine leaving groups of the firstrepeating units are not completely removed by the exposure process,remaining fluorine leaving groups may be removed from the firstrepeating unit by an acid (proton) from the PAG. Therefore, a conversionof the exposed portion 133 into a polar pattern and/or a hydrophilicpattern may be ensured.

Referring to FIG. 4, the exposed portion 133 of the photoresist layer130 may be selectively removed by, e.g., a developing process.Accordingly, a photoresist pattern 150 may be defined by the non-exposedportion 135 remaining on the object layer 110 or the anti-reflectivelayer 120.

In example embodiments, the exposed portion 133 may also be removed by adry etching process or alternatively be removed using a dry etchingprocess. The dry etching process may include a plasma etching process ora reactive ion etching (RIE) process using, e.g., an oxygen gas.

The exposed portion 133, as described above, may include a highlyhydrophilic and/or polar group such as carboxylic acid. Thus, theexposed portion 133 may have a relatively high affinity for the plasmaetching process or the RIE process. Therefore, the exposed portion 133may be selectively removed with a high etching selectivity relative tothe non-exposed portion 135.

In example embodiments, the exposed portion 133 may be removed by thedeveloping process. For example, an alcohol-based solution or ahydroxide-based solution such as tetra methyl ammonium hydroxide (TMAH)may be used as the developing solution. As described above, the exposedportion 133 may be converted to a pattern which may be remarkably polaror hydrophilic relatively to the non-exposed portion 135. Therefore, theexposed portion 133 may have a high solubility for the developingsolution relatively to the non-exposed portion 135, and thus may beselectively removed by the developing solution such as TMAH.

In a comparative example, while performing an exposure process in whicha chemically amplified resist (CAR) system using a PAG is implemented,an acid may be diffused into the non-exposed portion 135 to increase asurface roughness of the photoresist pattern 150. The non-exposedportion 135 may be also damaged by the acid, and thus the photoresistpattern 150 having desired width and/or pitch may not be obtained. As acritical dimension of the photoresist pattern 150 or a target patternformed by a photolithography process is decreased, a pattern damage bythe acid diffusion may be exacerbated.

In example embodiments, the acid from the PAG may be excluded, or may beused only by the catalytic amount. Thus, polar and/or hydrophilicproperties of the exposed portion 133 may be achieved substantially onlyby a reaction between the active fluorine and the silicon-containingleaving group. Therefore, a photolithography process system which may besubstantially free of the pattern damage caused by an irregular aciddiffusion may be realized. Further, the photoresist pattern 150 and thetarget pattern having desired fine width and/or pitch may be preciselyformed.

Referring to FIG. 5, the anti-reflective layer 120 and the object layer110 may be etched using the photoresist pattern 150 as an etching mask.Accordingly, an anti-reflective layer pattern 125 and an object layerpattern 115 may be formed between the photoresist pattern 150 and thesubstrate 100.

The etching process may include a dry etching process and/or a wetetching process properly selected in consideration of an etchingselectivity between the photoresist pattern 150 and the object layer110.

In example embodiments, the dry etching process may include a plasmaetching process.

In example embodiments, when performing the wet etching process, aproper etchant solution such as fluoric acid, phosphoric acid, sulfuricacid or peroxide may be selected depending on a material included in theobject layer 110.

Referring to FIG. 6, the photoresist pattern 150 and the anti-reflectivelayer pattern 125 may be removed such that the object layer pattern 115may remain on the substrate 100.

In example embodiments, the photoresist pattern 150 and theanti-reflective layer pattern 125 may be removed by an ashing processand/or a strip process. In example embodiments, the photoresist pattern150 and the anti-reflective layer pattern 125 may be removed by aplanarization process, e.g., a chemical mechanical polish (CMP) process.

If the object layer 110 includes a conductive material, the object layerpattern 115 may serve as a wiring, a contact, a pad, a plug, aninterconnection structure, or the like of a semiconductor device.

If the object layer 110 includes an insulative material, the objectlayer pattern 115 may serve as a desired (and/or alternativelypredetermined) insulation pattern, e.g., an insulating interlayerpattern, a filling insulation pattern, or the like. In exampleembodiments, a portion of the object layer 110 removed by theabove-mentioned photolithography process may be converted into a contacthole, an opening or a trench included in the insulation pattern.

FIGS. 7 to 14 are cross-sectional views illustrating a method of forminga pattern in accordance with example embodiments. For example, FIGS. 7to 14 illustrate a method of forming a conductive pattern utilizing theabove-mentioned photoresist polymer or the photoresist composition.

Detailed descriptions on processes and/or materials substantially thesame as or similar to those illustrated with reference to FIGS. 1 to 6are omitted herein.

Referring to FIG. 7, a lower contact 215 extending through a lowerinsulation layer 210 may be formed. A plurality of the lower contacts215 may be formed in the lower insulation layer 210.

In example embodiments, the lower insulation layer 210 may be formed ona passivation layer 200, and a contact hole extending through the lowerinsulation layer 210 and the passivation layer 200 may be formed. Thelower contact 215 may be formed by filling a conductive layer in thecontact hole by a deposition process or a plating process.

In example embodiments, the method of forming patterns in accordancewith example embodiments as described above may be implemented for theformation of the contact hole using the lower insulation layer 210 as anobject layer.

The lower insulation layer 210 may be formed of an insulative materialsuch as silicon oxide or silicon oxynitride. For example, the lowerinsulation layer 210 may be formed of a silicon oxide-based materialsuch as plasma enhanced oxide (PEOX), tetraethyl orthosilicate (TEOS),boro tetraethyl orthosilicate (BTEOS), phosphorous tetraethylorthosilicate (PTEOS), boro phospho tetraethyl orthosilicate (BPTEOS),boro silicate glass (BSG), phospho silicate glass (PSG), boro phosphosilicate glass (BPSG), or the like.

The passivation layer 200 may be formed of silicon nitride. Theconductive layer may be formed of a metal such as aluminum (Al),tungsten (W) or copper (Cu), or a metal nitride.

In example embodiments, the lower contact 215 may be electricallyconnected to a circuit device or a lower wiring formed on asemiconductor substrate. Damages of the circuit device or the lowerwiring while forming the contact hole may be limited and/or prevented bythe passivation layer 200.

A first etch-stop layer 220 may be formed on the lower insulation layer210 to cover the lower contacts 215. The first etch-stop layer 220 maybe formed of silicon nitride or silicon oxynitride. For example, thefirst etch-stop layer 220 may be formed by, e.g., a CVD process, a PECVDprocess, a spin coating process or an ALD process.

Referring to FIG. 8, an insulating interlayer 225, a buffer layer 230and a second etch-stop layer 235 may be sequentially formed on the firstetch-stop layer 220.

For example, the insulating interlayer 225 may be formed of theabove-mentioned silicon oxide-based material, or a polysiloxane-basedmaterial. The buffer layer 230 and the second etch-stop layer 235 may beformed of, e.g., silicon oxynitride and silicon nitride, respectively. Astress generated from the second etch-stop layer 235 may be alleviatedor absorbed by the buffer layer 230.

The insulating interlayer 225, the buffer layer 230 and the secondetch-stop layer 235 may be formed by a deposition process such as a CVDprocess, a PECVD process, a sputtering process such as an ion beamsputtering process, a spin coating process, or the like.

Referring to FIG. 9, a photoresist layer 240 may be formed on the secondetch-stop layer 235.

The photoresist layer 240 may be formed using the photoresistcomposition according to example embodiments. As described above, thephotoresist composition may include a photoresist polymer that mayinclude a repeating unit to which a silicon-containing leaving group maybe combined, a fluorine-containing source providing an active fluorine,and a solvent. The photoresist composition may optionally include asurfactant, a PAG and/or a sensitizer.

In example embodiments, the fluorine-containing source may beincorporated in the photoresist polymer. In this case, the photoresistpolymer may be a polymer from a first repeating unit including afluorine leaving group, and a second repeating unit including thesilicon-containing leaving group.

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2 or Chemical Formula 3.

In example embodiments, the fluorine-containing source may be providedas an organic salt solution or an inorganic salt solution of a fluorineion.

In example embodiments, the photoresist composition may be coated toform a preliminary photoresist layer, and the preliminary photoresistlayer may be cured by, e.g., a baking process to form the photoresistlayer 240.

Referring to FIG. 10, processes substantially the same as or similar tothose illustrated with reference to FIGS. 3 and 4 may be performed toform a photoresist pattern 250.

In example embodiments, an exposure process may be performed so that anactive fluorine including a fluorine ion or a fluorine radical may begenerated from the fluorine-containing source included in an exposedportion. The active fluorine may be transferred to thesilicon-containing leaving group. Accordingly, a photo-chemical reactionbetween the first and second repeating units may be induced by, e.g., amechanism as shown in Reaction Scheme 1, so that a hydrophilicity and/ora polarity of the exposed portion may be remarkably increased relativelyto a non-exposed portion.

In example embodiments, the buffer layer 230 may serve as ananti-reflective layer during the exposure process.

The exposed portion may be selectively removed by a developing processor a dry etching process such that the photoresist pattern 250 may beformed.

Referring to FIG. 11, the second etch-stop layer 235, the buffer layer230, the insulating interlayer 225 and the first etch-stop layer 220 maybe partially and sequentially etched using the photoresist pattern 250as an etching mask. Thus, an opening 260 through which the lower contact215 may be exposed may be formed.

The opening 260 may be formed by a dry etching process. The opening 260may extend through the insulating interlayer 225 and the first etch-stoplayer 220, and may at least partially expose an upper surface of thelower contact 215.

In example embodiments, the opening 260 may have a contact hole shapethrough which each lower contact 215 may be exposed. In exampleembodiments, the opening 260 may have a linear shape through which aplurality of the lower contacts 215 may be exposed.

Referring to FIG. 12, a conductive layer 270 filling the openings 260may be formed.

In example embodiments, a barrier layer 265 may be formed conformallyalong top surfaces and sidewalls of the photoresist pattern 250, andsidewalls and bottoms of the openings 260. The conductive layer 270 maybe formed on the barrier layer 265 to sufficiently fill the openings260.

The barrier layer 265 may be formed of a metal nitride such as titaniumnitride, tantalum nitride or tungsten nitride. The barrier layer 265 maylimit and/or prevent a metal ingredient in the conductive layer 270 frombeing diffused into the insulating interlayer 225. The barrier layer 265may also provide an adhesion for the formation of the conductive layer270. The barrier layer 265 may be formed by, e.g., a sputtering processor an ALD process.

The conductive layer 270 may be formed by, e.g., an electroplatingprocess. In this case, a seed layer may be formed conformally on thebarrier layer 265 by a sputtering process using a copper target. Aplating solution such as a copper sulfate solution may be prepared, anda current may be applied using the seed layer and the plating solutionas a cathode and an anode, respectively. Thus, the conductive layer 270including copper may be grown or precipitated on the seed layer throughan electrochemical reaction.

In example embodiments, the conductive layer 270 may be deposited by asputtering process using a metal target such as copper, tungsten oraluminum, or an ALD process.

Referring to FIG. 13, upper portions of the conductive layer 270 and thebarrier layer 265 may be planarized to form a conductive pattern 280.

In example embodiments, the upper portions of the conductive layer 270and the barrier layer 265 may be planarized by a CMP process until a topsurface of the insulating interlayer 225 is exposed. The photoresistpattern 250, the second etch-stop layer 235 and the buffer layer 230 maybe also removed by the planarization process.

Accordingly, the conductive pattern 280 electrically connected to thelower contact 215 may be formed in the opening 260. The conductivepattern 280 may include a barrier layer pattern 267 formed on thesidewall and the bottom of the opening 260, and a conductive layerpattern 275 filling a remaining portion of the opening 260 on thebarrier layer pattern 267.

FIGS. 12 and 13 illustrate that the photoresist pattern 250 is removedby the planarization process for the formation of the conductive pattern280. However, the photoresist pattern 250 may be removed after formingthe opening 260 and before forming the barrier layer 265. For example,after forming the opening 260, the photoresist pattern 250 may beremoved by an ashing process and/or a strip process.

In example embodiments, a cleaning process may be further performed toremove an etching residue including, e.g., a metal which may remain onthe insulating interlayer 225.

Referring to FIG. 14, a capping layer pattern 290 may be formed on anupper surface of the conductive pattern 280.

For example, a capping layer covering the conductive patterns 280 may beformed on the insulating interlayer 225, and the capping layer may bepartially etched to form the capping layer pattern 290 which may coverthe conductive pattern 280.

The capping layer may be formed of a metal that may be more chemicallystable than a metal included in the conductive pattern 280 by asputtering process or an ALD process. For example, the capping layer maybe formed using a metal such as aluminum, cobalt or molybdenum. Inexample embodiments, the capping layer may be formed of a nitride of themetal.

The capping layer may be patterned by a wet etching process using anetchant solution that may include peroxide such as hydrogen peroxide. Inexample embodiments, the capping layer may be self-aligned with theconductive pattern 280 by an affinity between metallic materials. Inthis case, the capping layer pattern 290 may be formed without anadditional patterning process.

In example embodiments, a build-up process may be further performed suchthat additional insulating interlayer, conductive pattern and/or upperwiring may be formed on the insulating interlayer 225 and the cappinglayer pattern 290. In this case, the conductive pattern 280 may serve asan interconnection structure electrically connecting the lower contact215 and the upper wiring to each other. In example embodiments, theconductive pattern 280 may serve as a wiring extending linearly, and maybe electrically connected to the plurality of the lower contacts 215.

As described above, the opening 260 for the formation of the conductivepattern 280 may be formed using the photoresist polymer or thephotoresist composition according to example embodiments.

As a width of the conductive pattern 280 and a distance between theconductive patterns 280 become decreased, a photolithography processhaving a high resolution may be needed. In example embodiments, anexposure process may be performed only through a photochemical reactionbetween the active fluorine and the silicon-containing leaving group.Thus, an irregular acid diffusion occurring in a CAR system-basedphotolithography process may be avoided. Therefore, the conductivepattern having a fine pitch and a fine dimension may be formed as adesired uniform profile, and a resolution of the photolithographyprocess may be improved.

Additionally, in the CAR system-based photolithography process, aphotoresist layer may be formed to have a thickness greater than atarget thickness of a photoresist pattern in consideration of a damageof the photoresist layer by the acid diffusion. However, in exampleembodiments, a photolithography process substantially free of the aciddiffusion may be realized. Thus, a thickness of the photoresist layermay be reduced because a thickness tolerance may not be needed, andfurther a process cost may be also reduced.

Methods of Manufacturing Semiconductor Devices

FIGS. 15 to 33 are top plan views and cross-sectional views illustratinga method of manufacturing a semiconductor device in accordance withexample embodiments.

Specifically, FIGS. 24, 27 and 29 are top plan views illustrating themethod. FIGS. 15 to 23, 25, 26, 28, and 30 to 33 are cross-sectionalviews taken along a line I-I′ indicated in FIGS. 24 and 27.

For example, FIGS. 15 to 33 illustrate a method of manufacturing avertical memory device including a channel extending vertically to a topsurface of a substrate.

In FIGS. 15 to 33, a direction substantially vertical to the top surfaceof the substrate is referred to as a first direction, and two directionssubstantially parallel to the top surface of the substrate andsubstantially crossing each other are referred to as a second directionand a third direction. For example, the second direction and the thirddirection are substantially perpendicular to each other. Additionally, adirection indicated by an arrow and a reverse direction thereof areconsidered as the same direction.

In example embodiments, the vertical memory device manufactured by themethod of FIGS. 15 to 33 may be a nonvolatile memory. The nonvolatilememory may be embodied to include a three dimensional (3D) memory array.The 3D memory array may be monolithically formed on a substrate (e.g.,semiconductor substrate such as silicon, or semiconductor-on-insulatorsubstrate). The 3D memory array may include two or more physical levelsof memory cells having an active area disposed above the substrate andcircuitry associated with the operation of those memory cells, whethersuch associated circuitry is above or within such substrate. The layersof each level of the array may be directly deposited on the layers ofeach underlying level of the array.

In example embodiments, the 3D memory array may include vertical NANDstrings that are vertically oriented such that at least one memory cellis located over another memory cell. The at least one memory cell maycomprise a charge trap layer. Each vertical NAND string may furtherinclude at least one select transistor located over memory cells. The atleast one select transistor may have the same structure with the memorycells and may be formed monolithically together with the memory cells.

The following patent documents, which are hereby incorporated byreference in their entirety, describe suitable configurations forthree-dimensional memory arrays, in which the three-dimensional memoryarray is configured as a plurality of levels, with word lines and/or bitlines shared between levels: U.S. Pat. Nos. 7,679,133; 8,553,466;8,654,587; 8,559,235; and US Pat. Pub. No. 2011/0233648.

Referring to FIG. 15, insulating interlayers 302 (e.g., 302 a to 302 g)and sacrificial layers 304 (e.g., 304 a to 304 f) may be alternately andrepeatedly formed on a substrate 300 to form a mold structure. Aphotoresist layer 310 may be formed on the mold structure or anuppermost insulating interlayer 302 g.

The substrate 300 may include a semiconductor material such as silicon,germanium, silicon-germanium, or the like. Alternatively, the substratemay include a semiconductor-on-insulator material (e.g., silicon oninsulator).

In example embodiments, the insulating interlayer 302 may be formed ofan oxide-based material, e.g., silicon dioxide, silicon carboxide and/orsilicon fluorooxide. The sacrificial layer 304 may be formed using amaterial that may have an etching selectivity with respect to theinsulating interlayer 302 and may be easily removed by a wet etchingprocess. For example, the sacrificial layer 304 may be formed of anitride-based material, e.g., silicon nitride and/or siliconboronitride.

The insulating interlayer 302 and the sacrificial layer 304 may beformed by a CVD process, a PECVD process, a spin coating process, etc. Alowermost insulating interlayer 302 a may be formed by a thermaloxidation process on the top surface of the substrate 300. In this case,the lowermost insulating interlayer 302 a may have a thin thicknessrelatively to other insulating interlayers 302 b through 302 g.

The sacrificial layers 304 may be removed in a subsequent process toprovide spaces for a ground selection line (GSL), a word line and astring selection line (SSL). Thus, the number of the insulatinginterlayers 302 and the sacrificial layers 304 may be adjusted inconsideration of the number of the GSL, the word line and the SSL. Forexample, each of the GSL and the SSL may be formed at a single level,and the word line may be formed at 4 levels. Accordingly, thesacrificial layers 304 may be formed at 6 levels, and the insulatinginterlayers 302 may be formed at 7 levels as illustrated in FIG. 15.However, the number of the GSL, the SSL and the word line may not belimited to the examples provided herein, and may be properly adjusted inconsideration of a degree of integration and a circuit design of thesemiconductor device.

The photoresist layer 310 may be formed using the photoresistcomposition according to example embodiments. As described above, thephotoresist composition may include a photoresist polymer that mayinclude a repeating unit to which a silicon-containing leaving group maybe combined, a fluorine-containing source providing an active fluorine,and a solvent. The photoresist composition may optionally include asurfactant, a PAG and/or a sensitizer.

In example embodiments, the fluorine-containing source may beincorporated in the photoresist polymer. In this case, the photoresistpolymer may be a polymer from a first repeating unit including afluorine leaving group, and a second repeating unit including thesilicon-containing leaving group.

In example embodiments, the photoresist polymer may be represented bythe above Chemical Formula 2 or Chemical Formula 3.

In example embodiments, the fluorine-containing source may be providedas an organic salt solution or an inorganic salt solution of a fluorineion.

The photoresist composition may be coated to form a preliminaryphotoresist layer, and the preliminary photoresist layer may be curedby, e.g., a baking process to form the photoresist layer 310. In exampleembodiments, an anti-reflective layer may be further formed before theformation of the photoresist layer 310.

Referring to FIG. 16, a process substantially the same as or similar tothat illustrated with reference to FIG. 3 may be performed.

In example embodiments, an exposure mask exposing a lateral portion oran end portion of the photoresist layer 310 may be placed on thephotoresist layer 310, and an exposure process may be performed.Accordingly, the lateral portion and the end portion of the photoresistlayer 310 may be converted into an exposed portion 313 having anincreased hydrophilicity and/or polarity by a photo-chemical reaction.

As described above, the active fluorine including a fluorine ion or afluorine radical may be generated from the fluorine-containing sourceincluded in the exposed portion 313. The active fluorine may betransferred to the silicon-containing leaving group. Accordingly, thephoto-chemical reaction between the first and second repeating units maybe induced by, e.g., a mechanism as shown in Reaction Scheme 1, so thatthe hydrophilicity and/or polarity of the exposed portion 313 may beremarkably increased relatively to a non-exposed portion.

Referring to FIG. 17, a process substantially the same as or similar tothat illustrated with reference to FIG. 4 may be performed to remove theexposed portion 313.

In example embodiments, the exposed portion 313 may be selectivelyremoved by a developing process or a dry etching process.

Referring to FIG. 18, lateral portions or end portions of the insulatinginterlayers 302 b to 302 g, and the sacrificial layers 304 a to 304 fmay be etched using the photoresist layer 310 having a reduced width asan etching mask.

Referring to FIG. 19, processes substantially the same as or similar tothose illustrated with reference to FIGS. 16 and 17 may be repeated.Accordingly, a lateral portion or an end portion of the remainingphotoresist layer 310 may be removed, such that a width of thephotoresist layer 310 may be reduced again.

Referring to FIG. 20, lateral portions or end portions of the insulatinginterlayers 302 c to 302 g, and the sacrificial layers 304 b to 304 fmay be etched using the photoresist layer 310 having the reduced widthas an etching mask.

Referring to FIG. 21, processes substantially similar to thoseillustrated with reference to FIGS. 19 and 20 may be repeated. Forexample, a reduction of width of the photoresist layer 310, and etchingprocesses of the insulating interlayers 302 and the sacrificial layers304 may be repeated to form a stepped mold structure including aplurality of steps or stairs.

As described above, a plurality of exposure processes may be repeated onthe photoresist layer 310 for the formation of the stepped moldstructure. As the exposure processes are repeatedly performed, athickness of the photoresist layer 310 may be gradually decreased. Forexample, in the above-mentioned CAR system-based photolithographyprocess, the photoresist layer 310 may be excessively damaged by an aciddiffusion before the formation of the stepped mold structure.

However, according to example embodiments, the exposed portion 313having the increased hydrophilicity and/or polarity relative to aremaining portion of the photoresist layer 310 may be formed by thephoto-chemical reaction between the active fluorine and thesilicon-containing leaving group without an involvement of an acid. Theexposed portion 313 may be selectively removed by the developing processor the dry etching process without damaging the non-exposed photoresistlayer 310.

Therefore, even though the exposure processes may be repeatedlyperformed, durability and stability of the photoresist layer 310 may bemaintained, and a target thickness of the photoresist layer 310 may bedecreased.

The remaining photoresist layer 310 after the formation of the steppedmold structure may be removed by an ashing process and/or a stripprocess.

The photolithography process for the formation of the stepped moldstructure may be concurrently performed at both lateral portions of themold structure. In this case, the stepped mold structure may have asubstantially pyramidal shape.

Referring to FIG. 22, a mold protection layer 315 covering a lateralsurface of the stepped mold structure may be formed.

For example, an insulation layer covering the stepped mold structure maybe formed on the substrate 300 using, e.g., silicon oxide by a CVDprocess or a spin coating process. An upper portion of the insulationlayer may be planarized by a CMP process until the uppermost insulatinginterlayer 302 g is exposed to form the mold protection layer 315.

Referring to FIGS. 23 and 24, a plurality of channel holes 320 may beformed through the insulating interlayers 302 and the sacrificial layers304. For example, a hard mask (not illustrated) may be formed on theuppermost insulating interlayer 302 g and the mold protection layer 315.The insulating interlayers 302 and the sacrificial layers 304 may bepartially etched by, e.g., a dry etching process. The hard mask may beused as an etching mask to form the channel hole 320. A top surface ofthe substrate 300 may be partially exposed by the channel hole 320.

The hard mask may be formed of silicon-based or carbon-based spin-onhardmask (SOH) materials, or polysilicon. After the formation of thechannel hole 320, the hard mask may be removed by an ashing processand/or strip process.

In example embodiments, the channel hole 320 may be formed by themethods of forming patterns utilizing the photoresist polymer or thephotoresist composition in accordance with example embodiments.

For example, a photoresist layer may be formed on the uppermostinsulating interlayer 302 g and the mold protection layer 315 asdescribed with reference to FIG. 2. A portion of the photoresist layeroverlapping a region for the channel hole 320 may be converted to anexposed portion having an increased hydrophiliciy and/or polarity asdescribed with reference to FIG. 3. As described with reference to FIG.4, the exposed portion may be removed to form a photoresist pattern, theinsulating interlayers 302 and the sacrificial layers 304 may bepartially etched using the photoresist pattern as an etching mask toform the channel hole 320.

In example embodiments, the channel hole 320 may extend in the firstdirection, and a plurality of the channel holes 320 may be formed alongthe third direction to form a channel hole row. A plurality of thechannel hole rows may be formed along the second direction.

Referring to FIG. 25, a dielectric layer structure 330 may be formed ona sidewall of the channel hole 320, and a channel layer 333 and a firstfilling layer 335 filling the channel hole 320 may be formed on thedielectric layer structure 330.

In example embodiments, a dielectric layer may be formed along topsurfaces of the uppermost insulating interlayer 302 g and the moldprotection layer 315, and the sidewalls and bottoms of the channel holes320. Portions of the dielectric layer formed on the top surfaces of theuppermost insulating interlayer 302 g and the mold protection layer 315,and the bottoms of the channel holes 320 may be removed by an etch-backprocess. Accordingly, the dielectric layer structure 330 having, e.g., astraw shape may be formed in the sidewall of each channel hole 320.

In example embodiments, the dielectric layer may include a blockinglayer, a charge storage layer and a tunnel insulation layer sequentiallystacked from the sidewall of the channel hole 320. For example, thedielectric layer may have an oxide-nitride-oxide (ONO) layeredstructure.

A channel layer 333 may be formed conformally on the uppermostinsulating interlayer 302 g, a top surface and an inner sidewall of thedielectric layer structure 330, and the top surface of the substrate 300exposed through the channel hole 320. The first filling layer 335sufficiently filling a remaining portion of the channel hole 320 may beformed on the channel layer 333.

The channel layer 333 may be formed using polysilicon or amorphoussilicon which is optionally doped with impurities. In exampleembodiments, a heat treatment or a laser beam irradiation may be furtherperformed on the channel layer 333. In this case, the channel layer 333may include single crystalline silicon. The first filling layer 335 maybe formed using an insulative material, e.g., silicon oxide.

Referring to FIGS. 26 and 27, upper portions of the first filling layer335 and the channel layer 333 may be planarized by, e.g., a CMP processuntil the uppermost insulating interlayer 302 g is exposed.

Accordingly, a channel 334 and a first filling layer pattern 336surround by the dielectric layer structure 330 may be formed in thechannel hole 310. The channel 334 may have a cup shape, and a lowerportion of the channel 334 may be in contact with the top surface of thesubstrate 300. The first filling layer pattern 336 may have a pillarshape accommodated in the channel 334.

In example embodiments, after the formation of the channel hole 320 andbefore the formation of the dielectric layer structure 330, asemiconductor pattern may be further formed at a lower portion of thechannel hole 320. The semiconductor pattern may be formed by a selectiveepitaxial growth (SEG) process using the top surface of the substrate300 as a seed. In this case, the dielectric layer structure 330 and thechannel 334 may be formed on a top surface of the semiconductor pattern.

After the formation of the channel 334 in each of the channel holes 320,a channel row comparable to the channel hole row may be defined, and aplurality of the channel rows may be arranged along the seconddirection.

Referring to FIG. 28, a pad 340 filling an upper portion of the channelhole 330 may be formed.

For example, upper portions of the dielectric layer structure 330, thechannel 334 and the first filling layer pattern 336 may be partiallyremoved by, e.g., an etch-back process to form a recess. A pad layer maybe formed on the uppermost insulating interlayer 302 g and the moldprotection layer 315 to sufficiently fill the recess. An upper portionof the pad layer may be planarized until a top surface of the uppermostinsulating interlayer 302 g is exposed to form the pad 340 from aremaining portion of the pad layer. In example embodiments, the padlayer may be formed using polysilicon optionally doped with n-typeimpurities. In example embodiments, a preliminary pad layer includingamorphous silicon may be formed, and then a crystallization process maybe performed thereon to form the pad layer.

Referring to FIG. 29, the stepped mold structure and the mold protectionlayer 315 may be partially etched to form an opening 350.

For example, a hard mask (not illustrated) covering the pads 340 andpartially exposing the uppermost insulating interlayer 302 g and themold protection layer 315 between some of the channel rows may beformed. The mold protection layer 315, the insulating interlayers 302and the sacrificial layers 304 may be partially etched by, e.g., a dryetching process using the hard mask as an etching mask to form theopening 350. The hard mask may be formed using a photoresist material oran SOH material. The hard mask may be removed by an ashing processand/or a strip process after the formation of the opening 350.

The opening 350 may extend in the third direction, and a plurality ofthe openings 350 may be formed along the second direction by a desired(and/or alternatively predetermined) distance. For example, the desired(and/or alternatively predetermined) number of the channel rows may beincluded between the openings 350 neighboring in the second direction.

The opening 350 may also extend through the stepped mold structure inthe first direction. The top surface of the substrate 300 may be exposedthrough a bottom of the opening 350, and the insulating interlayers 302and the sacrificial layers 304 may be exposed through a sidewall of theopening 350.

Referring to FIG. 30, the sacrificial layers 304 which are exposed bythe sidewall of the opening 350 may be removed.

In example embodiments, if the sacrificial layer 304 includes siliconnitride, and the insulating interlayer 302 includes silicon oxide, thesacrificial layers 304 may be removed by a wet etching process using,e.g., phosphoric acid that may have an etching selectivity for siliconnitride as an etchant solution.

A gap 355 may be defined by a space from which the sacrificial layer 304is removed. A plurality of the gaps 355 may be formed along the firstdirection. An outer sidewall of the dielectric layer structure 330 maybe at least partially exposed by the gap 355.

Referring to FIG. 31, a gate line 360 may be formed in the gap 355 ateach level.

For example, a gate electrode layer may be formed along the exposedouter sidewall of the dielectric layer structure 330, surfaces of theinsulating interlayers 302, top surfaces of the mold protection layer315 and the pad 340, and the top surface of the substrate 300 exposedthrough the opening 350. The gate electrode layer may sufficiently fillthe gaps 355, and may partially fill the opening 350.

The gate electrode layer may be formed using a metal or a metal nitridehaving low electrical resistance and work function. For example, thegate electrode layer may be formed using tungsten, tungsten nitride,titanium, titanium nitride, tantalum, tantalum nitride, platinum, etc.The gate electrode layer may be formed by a CVD process, a PECVDprocess, an ALD process, a PVD process, a sputtering process, etc.

The gate electrode layer may be partially etched to form the gate line360 in the gap 355 at the each level.

For example, an upper portion of the gate electrode layer may beplanarized by a CMP process until the uppermost insulating interlayer302 g or the mold protection layer 315 is exposed. Portions of the gateelectrode layer formed in the opening 350 and on the top surface of thesubstrate 300 may be etched to obtain the gate lines 360 (e.g., 360 a to360 f). The gate electrode layer may be partially etched by a wetetching process using, e.g., a hydrogen peroxide-containing solution.

The gate lines 360 may include the GSL, the word line and the SSLsequentially stacked and spaced apart from one another in the firstdirection. For example, a lowermost gate line 360 a may serve as theGSL. Four gate lines 360 b to 360 e on the GSL may serve as the wordlines. An uppermost gate line 360 f on the word line may serve as theSSL. However, the stacked number of the GSL, the word line and the SSLmay be properly adjusted in consideration of a circuit design and/or adegree of integration of the vertical memory device.

The gate line 360 at the each level may surround the channel rowsbetween the openings 350 neighboring in the second direction, and mayextend in the third direction. The gate lines 360 may be stacked in thefirst direction to form a stepped structure. Accordingly, the gate line360 may include an extended portion protruding in the third direction.

After the formation of the gate lines 360, e.g., n-type impurities maybe implanted through the top surface of the substrate 300 exposedthrough the opening 350 to form an impurity region (not illustrated).For example, the impurity region may serve as a common source line (CSL)extending in the third direction.

A second filling layer (not illustrated) filling the opening 350 may beformed on the impurity region. For example, the second filling layer maybe formed of silicon oxide by a CVD process.

Referring to FIG. 32, first contacts 370 (e.g., 370 a to 370 e)electrically connected to the gate lines 360 may be formed.

In example embodiments, the mold protection layer 315 and the insulatinginterlayers 302 may be partially etched to form the contact holesexposing the extended portion of the gate line 360 at the each level. Afirst conductive layer filling the contact holes may be formed on themold protection layer 315. An upper portion of the first conductivelayer may be planarized by a CMP process until a top surface of the moldprotection layer 315 is exposed to form the first contacts 370.

In example embodiments, the contact hole may be formed by the methods offorming patterns utilizing the photoresist polymer or the photoresistcomposition in accordance with example embodiments.

For example, a photoresist layer may be formed on the uppermostinsulating interlayer 302 g, the pad 340 and the mold protection layer315 as described with reference to FIG. 2. Portions of the photoresistlayer overlapping regions for the contact holes may be converted to anexposed portion having an increased hydrophiliciy and/or polarity asdescribed with reference to FIG. 3. As described with reference to FIG.4, the exposed portion may be removed to form a photoresist pattern. Themold protection layer 315 and the insulating interlayer 302 may bepartially etched using the photoresist pattern as an etching mask toform the contact holes.

For example, some of the first contacts 370 (e.g., 370 b to 370 e) maybe electrically connected to the gate lines 360 serving as the wordlines (e.g., 360 b to 360 e). In this case, the extended portions of thegate lines 360 b to 360 e may serve as a word line pad. In exampleembodiments, the lowermost first contact 370 a may be electricallyconnected to the gate line 360 a serving as the GSL.

Referring to FIG. 33, an upper insulation layer 380 may be formed on theuppermost insulating interlayer 302 g, the mold protection layer 315,the pad 340, the second filling layer and the first contacts 370. Forexample, the upper insulation layer 380 may be formed of silicon oxideby a CVD process or a spin coating process. The upper insulation layer380 may be partially etched to form holes or openings exposing the pad340 and the first contacts 370. A second conductive layer filling theholes or the openings may be formed on the upper insulation layer 380,and may be planarized until a top surface of the upper insulation layer380 is exposed to form a channel contact 387 and a second contact 385.

In example embodiments, the holes and the openings may be formed by themethods of forming patterns utilizing the photoresist polymer or thephotoresist composition according to example embodiments, and using theupper insulation layer 380 as an object layer.

The channel contact 387 may be in contact with the pad 340 and may beelectrically connected to the channel 334. The second contact 385 may bein contact with the first contact 370.

The first and second conductive layers may be formed using a metal suchas tungsten or copper, or a nitride thereof by an ALD process or asputtering process.

In example embodiments, conductive lines electrically connected to thechannel contact 387 and the second contact 385 may be formed on theupper insulation layer 380.

Some of the conductive lines may extend in, e.g., the second directionto serve as a bit line electrically connected to a plurality of thechannel contacts 387. Some of the conductive lines may be electricallyconnected to the second contacts 385. In example embodiments, the secondcontact 385 may extended in the second direction, and may serve as awiring electrically connected to a plurality of the first contacts 370.

According to example embodiments of inventive concepts, the photoresistpolymer or the photoresist composition may include a fluorine-containingsource and a repeating unit having a silicon-containing leaving group.For example, after forming a photoresist layer, an exposure process maybe performed using a UV light source so that an active fluorine may begenerated from the fluorine-containing source to remove thesilicon-containing leaving group. Accordingly, the silicon-containinggroup may be replaced with a hydrophilic group such as a hydroxyl groupor carboxylic acid. Therefore, an etching rate and a polarity of thephotoresist layer may be differentiated at an exposed portion and anon-exposed portion thereof, and a photoresist pattern having a highresolution may be formed even without an assistance of a PAG.

The photoresist composition or the photoresist polymer in accordancewith example embodiments may be used in a photolithography process for aformation of a fine pattern having a dimension of, e.g., about 20 nm.Wirings, contacts, insulation patterns, etc., of various semiconductordevices such as flash memory devices, DRAM or MRAM devices or a logicdevice may be formed by the photolithography process with highresolution and reliability.

The foregoing is illustrative of example embodiments and is not to beconstrued as limiting thereof. Although a few example embodiments havebeen described, those skilled in the art will readily appreciate thatmany modifications are possible in the example embodiments withoutmaterially departing from the novel teachings and advantages ofinventive concepts. Accordingly, all such modifications are intended tobe included within the scope of inventive concepts as defined in theclaims. In the claims, means-plus-function clauses are intended to coverthe structures described herein as performing the recited function andnot only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofvarious example embodiments and is not to be construed as limited to thespecific example embodiments disclosed, and that modifications to thedisclosed example embodiments, as well as other example embodiments, areintended to be included within the scope of the appended claims.

While some example embodiments have been particularly shown anddescribed, it will be understood by one of ordinary skill in the artthat variations in form and detail may be made therein without departingfrom the spirit and scope of the claims.

1-13. (canceled)
 14. A method of forming a pattern, comprising: forminga photoresist layer on an object layer, the photoresist layer includinga photoresist polymer, the photoresist polymer including a firstrepeating unit and a second repeating unit, the first repeating unitincluding a fluorine leaving group, and the second repeating unitincluding a silicon-containing leaving group; performing an exposureprocess on the photoresist layer to induce a reaction between thefluorine leaving group and the silicon-containing leaving group; andforming a photoresist pattern by removing an exposed portion of thephotoresist layer.
 15. The method of claim 14, wherein the performingthe exposure process includes inducing an elimination reaction in thefirst repeating unit so that the fluorine leaving group is separatedfrom the first repeating unit.
 16. The method of claim 15, wherein theperforming the exposure process includes increasing a degree ofunsaturation at the exposed portion by the exposure process.
 17. Themethod of claim 15, wherein the reaction induced by the performing theexposure process includes separating the fluorine leaving groupseparated from the first repeating unit and transferring the separatedfluorine leaving group to the second repeating unit to attack thesilicon-containing leaving group.
 18. The method of claim 17, whereinthe exposed portion is more hydrophilic and polar than a non-exposedportion of the photoresist layer after the performing the exposureprocess .
 19. The method of claim 18, wherein the reaction induced bythe performing the exposure process includes removing thesilicon-containing leaving group from the exposed portion so that ahydroxyl group or a carboxylic group is created in the exposed portion.20. The method of claim 14, wherein the removing the exposed portion ofthe photoresist layer includes performing a developing process or a dryetching process.
 21. The method of claim 14, wherein the photoresistpolymer is represented by Chemical Formula 2:

wherein, in Chemical Formula 2, R₁ and R₅ are each independently adivalent group selected from styrene, hydroxystyrene, acrylate, C₁-C₆alkylene, arylene, carbonyl, oxy, a C₂-C₃₀ unsaturated aliphatic group,and a combination thereof, R₂, R₃ and R₄ are independently hydrogen, aC₁-C₂₀ alkyl group, a C₃-C₂₀ cycloalkyl group or a C₆-C₃₀ aromaticgroup, and R₂, R₃ and R₄ are the same as or different from each other,R₅ is a C₁-C₂₀ alkyl group, a C₁-C₂₀ allyl group, a C₃-C₂₀ cycloalkylgroup, a C₆-C₃₀ aromatic group, a hydroxyl group, a hydroxyalkyl group,or a C₁-C₂₀ alkoxy group, and each a and b represents a mole ratioranging from about 0.4 to about 0.6, and a sum of a and b is
 1. 22. Themethod of claim 14, further comprising: patterning the object layerusing the photoresist pattern as an etching mask.
 23. A method offorming a pattern, comprising: forming a photoresist layer on an objectlayer by coating a photoresist composition on the object layer, thephotoresist composition including a photoresist polymer, a solvent, anda fluorine-containing source configured to provide an active fluorine,the photoresist polymer including a repeating unit combined with asilicon-containing leaving group ; performing an exposure process on thephotoresist layer so that the active fluorine is transferred from thefluorine-containing source to the silicon-containing leaving group; andremoving an exposed portion of the photoresist layer to form aphotoresist pattern.
 24. The method of claim 23, wherein the activefluorine includes one of a fluorine ion and a fluorine radical.
 25. Themethod of claim 24, wherein the photoresist composition further includesat least one of a photoacid generator and a sensitizer.
 26. The methodof claim 23, wherein the fluorine-containing source is one of providedas a fluorine ion salt or incorporated in the photoresist polymer as arepeating unit thereof.
 27. The method of claim 23, wherein theperforming the exposure process includes: inducing a reaction thatcombines the active fluorine with the silicon-containing leaving group,and removing the active fluorine combined with the silicon-containingleaving group from the photoresist polymer. 28-30. (canceled)
 31. Amethod of forming a pattern, comprising: forming a photoresist layer onan object layer, the photoresist layer including a photoresist polymerincludes a repeating unit that includes a silicon-containing leavinggroup, the photoresist layer including a fluorine source configured toprovide active fluorine in response to exposure from light; performingan exposure process on the photoresist layer to separate the activefluorine from the fluorine source, the performing the exposure processincluding inducing a reaction between the active fluorine and thesilicon-containing leaving group that removes the silicon-containingleaving group from the photoresist polymer; and forming a photoresistpattern by removing an exposed portion of the photoresist layer.
 32. Themethod of claim 31, wherein the photoresist polymer includes a firstrepeating unit that includes a fluorine leaving group configured to beremoved by the exposure process, the fluorine leaving group is thefluorine source, the repeating unit that includes the silicon-containingleaving group is a second repeating unit.
 33. The method of claim 31,wherein the fluorine source includes a salt solution of a fluorine ion.34. The method of claim 31, wherein the repeating unit includes one ofsilyl ether and a functional group represented by Chemical Formula 1:

wherein, in Chemical Formula 1, R₁ is a divalent group selected fromstyrene, hydroxystyrene, acrylate, C ₁-C₆ alkylene, arylene, carbonyl,oxy, a C₂-C₃₀ unsaturated aliphatic group, and a combination thereof,and R₂, R₃ and R₄ are independently hydrogen, a C₁-C₂₀ alkyl group, aC₃-C₂₀ cycloalkyl group or a C₆-C₃₀ aromatic group, and R₂, R₃ and R₄are the same as or different from each other.
 35. The method of claim31, wherein the performing the exposure process includes increasing ahydrophilicity and a degree of unsaturation at the exposed portion bythe exposure process.
 36. A method of manufacturing a semiconductordevice, comprising: forming a mold structure by alternately andrepeatedly stacking insulating interlayers and sacrificial layers on asubstrate; performing the method of claim 31 to form the photoresistpattern on the mold structure; removing a portion of the mold structureusing the photoresist pattern as an etching mask; forming a plurality ofvertical channels through a central portion of the mold structure; andreplacing the sacrificial layers with gate lines.